Fig. 4.
Maintenance of Shh expression in the zone of polarizing activity requires Tcf3–β-catenin interaction. (A-B′) Whole-mount in situ hybridization using a cRNA probe specific for Shh mRNA in E9.5 (A,A′) and E10.0 (B,B′) mouse embryos. Higher magnification views of forelimbs are shown in C-D′. (C-N′) Whole-mount in situ hybridization of WT (C-N) and KI (C′-N′) limb buds using labeled cRNA probes for Shh (C-D′), patched 1 (E-F′), Fgf8 (G-H′), gremlin 1 (I-J′), Msx1 (K-L′) and Msx2 (M-N′). Two stages of development observed in E10 embryos are shown that correspond to the 30- to 31-somite (C,C′,E,E′,G,G′,I,I′,K,K′,M,M′) and 33- to 34-somite (D,D′,F,F′,H,H′,J,J′,L,L′,N,N′) stages.